Rolling method and apparatus for producing h-shaped steel products having flanges of different thicknesses and similarly shaped steel products

ABSTRACT

A rolling method and apparatus for producing such shaped products as asymmetrical H-shaped steel products having flanges of different thicknesses by using the universal rolling mill having a pair of vertical rolls, one having greater diameter than the other, thereby making equal or nearly equal the projected lengths of biting contact of these vertical rolls on the rolled material.

United States Patent Inventor Kanichl Kishikawa Fukuoka, Japan Appl No782,174

Filed Dec. 9, i968 Patented June 8, 1971 Assignee Nippon SteelCorporation Tokyo, Japan Priority Dec. 16, 1967 Japan 42/80439 ROLLINGMETHOD AND APPARATUS FOR PRODUCING H-SHAPED STEEL PRODUCTS HAVINGFLANGES OF DIFFERENT THICKNESSES AND SIMILARLY SHAPED STEEL PRODUCTS 3Claims, 6 Drawing Figs.

U.S. Cl 72/225 Int. Cl B2lb 13/10 [50] Field of Search ..72/225, 366

156] References Cited UNITED STATES PATENTS 431,623 7/I890 Sack...72/225 657,964 9/1900 Seaman 72/225X 3 342,053 9/1967 Stammbach 72/225XPrimary Examiner-Milton S. Mehr A ttorney-Wenderoth, Lind and PonackABSTRACT: A rolling method and apparatus for producing such shapedproducts as asymmetrical H-shaped steel products having flanges ofdifferent thicknesses by using the universal rolling mill having a pairof vertical rolls, one having greater diameter than the other, therebymaking equal or nearly equal the projected lengths of biting contact ofthese vertical rolls on the rolled material.

PATENTEI] JUN sum 3583193 SHEEI1UF3 FIG. IA FIG. IB

.FIG. 2

PRIOR ART KANI CHI KI 51 11 KAWA INVENTOR ATTORNEY PATENTED JUN 81971 353193 sum 2 [IF 3 KANI CHI KI SHIKAWA,

INVENTOR PATENTED JUN a IEIYI 3583193 sum 3 [IF 3 KANI CHI KI SHI KAWA,

INVENTOR BY [dZaM M ATTORNEY ROLLING METHOD AND APPARATUS FOR PRODUCINGH-SHAPED STEEL PRODUCTS HAVING FLANGES OF DIFFERENT THICKNESSES ANDSIMILARLY SHAPED STEEL PRODUCTS BACKGROUND OF THE INVENTION 1. Fieldofthe Invention v The present invention relates to a rolling method andapparatus for producing H-shaped steel products having flanges ofdifferent thicknesses, rails, etc. by using a universal rolling mill.

2. Description ofthe Prior Art It has long been well known that, ingeneral, the greater the size of the parts of H-shaped steel productshaving flanges on both sides of a web or other similarly shaped productssuch as rails, the more difficult is rolling by conventional rollpasses, using horizontal rolls only. The invention of the universalrolling mill using vertical rolls in addition to horizontal rolls, hasnearly solved the above problem. Not only has the rolling process usingthe universal rolling mill solved the problem of the size limit of theflanges ofshaped steel products, but also it is effective in suchrolling operations concentratedly carried out on the head of such steelproducts as rails which require heavy forging.

However, the universal rolling mill is not completely free fromproblems. When producing H-shaped steel products having flanges ofdifferent thicknesses, such as rails or the like, with the ordinary typeof universal rolling mill having vertical rolls of the same diameter,the rolled material tends to bend and twist while rolled, causinginaccurate size-stability of the product or, at the worst, making itimpossible to finish rolling, for such reasons as the difference instretching rate of the two flanges and the difference in horizontalpressure of the two vertical rolls. That is to say, it is impossible forthe universal rolling mill having vertical rolls of the same diameter toroll the material to produce such products having flanges of differentthicknesses such as H-shaped steel products and rails.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a rolling method and apparatus for rolling the material by usingthe universal rolling mill with the vertical rolls having been soarranged as to have different diameters, into such shaped products asH-shaped steel products having flanges of different thicknesses, such asrails.

Another object of the present invention is to provide a universalrolling mill capable of rolling the material easily and accurately intosuch shaped products as H-shaped steel products and rails, whichhasheretofore been impossible with the conventional universal rolling mill.

In order to achieve the above objects of the present invention, in theproduction of such shaped products as H-shaped steel products havingflanges of different thicknesses and rails by using the universalrolling mill, a pair of the vertical rolls of the universal rolling millare so constructed that the diameter of one of them is made smaller thanthat of the other in correspondence with the difference in thickness ofthe flanges of the to-be-made product, thereby making equal or nearlyequal the projected lengths of biting contact of these vertical rolls onthe rolled material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an example of shapedsteel products to be rolled by the method and apparatus of the presentinvention; FIG. 1 (A) and (B) show steel products shaped like rails andH-shaped steel products, respectively.

FIG. 2 is the longitudinal section of the conventional mill when rollingthe material into a l-I-shaped steel product having flanges of differentthicknesses to show the relation between the vertical roll and thematerial.

FIG. 3 is schematic diagram of the vertical roll of the conventionalmill when operating, to show the relation with the material incomparison with the relation when operating the mill of the presentinvention.

FIG. 4 is another example similar to that shown in FIG. 3.

FIG. 5 is the longitudinal section of the rolling apparatus of thepresent invention when operated by the method of the present inventionto produce a rail, and showing the relation between the vertical rolland the material.

DESCRIPTION OF THE PREFERRED EMBODIMENT The following is explanation ofa preferred embodiment of the present invention, in comparison withwhich is attached the practice of the conventional method to make theexplanation more understandable.

It is difficult for the conventional type of the universal rolling millhaving vertical rolls of same diameter to roll the material into suchshaped steel products having flanges of different thicknesses asH-shaped steel products.

The above difficulty is due mainly to the difference in stretching ratebetween the two flanges, and also due to the difference in horizontalpressure acting on the two vertical rolls. With reference to FIG. 2 andFIG. 3, horizontal pressure acting on the vertical rolls of theuniversal rolling mill may be generalized, as follows:

Horizontal pressure P P=f B 2 Where:

f: Deformity resistance l g./mm. B: Height of flange of the rolledmaterial e: Projected length of biting contact; ZRAh (R: Diameter of thevertical roll) (h: Reduction) If a final product having the thinnerflange 2.5 times higher than the thicker flange and the thicker flangetwice thicker than the thinner flange is to be produced with a universalrolling mill having vertical rolls of the same diameter, the horizontalpressure acting on the vertical roll havingthe thicker flange P,, andthat acting on the vertical roll having the thinner flange P, areformulated, as follows:

Therefore, P,, P,

The imblance of horizontal pressure acting on the vertical rolls 1 and 2causes the following problems: The vertical roll 1 which is effected bygreater vertical pressure tends to push the horizontal rolls 4 and 4'through the thinner flange 6 to the left. As the distance between thevertical rolls 1 and 2 is maintained a predetermined constant, the abovesideslip (transverse) of the horizontal rolls 4 and 4 affects theformation of the thicker flange 5 placed between these rolls and theother vertical roll 2. If this is left unadjusted, it will becomeimpossible to obtain products of accurate size. In order to preventsideslip of the horizontal rolls, prior art device called a thrustmetal" is set on the neck of the horizontal roll in the roll housing.This device, however, is not desirable for such rolling methods as thatof the present invention which is accompanied with extremely greathorizontal pressure, for the following reasons: The thrust metal issubjected to severe abrasion; the thickness of product is inconstant; itrequires time and labor for repairs, hampering smooth rollingoperations; and also its complicated structure enhances constructioncosts.

Another difficulty is that the vertical rolls 1 and 2 contact the rolledmaterial at different points, therefore, as shown in FIG. 3, the lineconnecting the contact point Q of the thicker flange 5 of the rolledmaterial and the contact point Q of the thinner flange 6 ofthe rolledmaterial. which is rolled between the vertical rolls 1 and 2 and betweenthe horizontal rolls 4 and 4' and the line connecting the centers and Orespec tively, of the vertical rolls 1 and 2 are not parallel Therefore,when the rolled material enters between the vertical rolls at a rightangle to the axes of the vertical rolls O and 0 the contact point Qcontacts the rolls earlier than the contact point Q causing the abovementioned horizontal pressure P,, to produce a bending moment whichbends the rolled material in the direction indicated by arrow 7 untilthe line connecting the contact points Q, and Q becomes parallel withthe line connecting the centers 0 and 0 In this case, the rolledmaterial is rubbed down" by the sidewall of the horizontal rolls 4 and4', such rub producing scratches on the surface of the rolled material.

For the above-mentioned reasons it is difficult for the ordinaryuniversal rolling mill to produce I-l-shaped steel products havingflanges of different thicknesses.

The above is an explanation of the present invention using an example ofrolling a prefigured steel piece which, before being fed into theuniversal rolling mill, has a size and shape similar to those of thedesired final product, that is, the part to become the thicker flange ofthe final product made thicker than the part to become the thinnerflange of the final product. This explanation can also apply to therolling of a prefigured steel piece having the same thickness for partsto become the flanges of the final product, into a final product havingflanges of different thicknesses.

If the same size of the final product as mentioned above is intended,

This means that the line connecting Q and Q which are the contact pointsof the rolled material respectively with the vertical rolls 1 and 2 isnot parallel with the line connecting the centers 0, and 0 of the rolls.Thus, the problems as mentioned above will take place on the side of theopposite roll 2,

The present invention is intended to solve these problems by adjustingthe diameter of the vertical rolls for rolling to produce, above all,H-shaped steel products having flanges of different thicknesses or othersteel products ofa similar shape. The special characteristics of thepresent invention relating to a rolling method and apparatus forproducing such asymmetrical steel products as I-I-shaped steel productshaving flanges of different thicknesses with the universal rolling mill,consist in that the diameter of one vertical roll is made greater thanthat of the other vertical roll, thereby making equal or nearly equalthe projected lengths of biting contact of the vertical rolls on therolled material.

Thus, Q and O or Q and Q which are the contact points of respectivevertical rolls with the rolled material become parallel, and thedifference, if any, of horizontal pressure will not cause bending momenton the rolled material, thus making possible rolling without bending.Also, as mentioned below, any difference in horizontal pressure may bedirected in a predetermined direction so as to have the vertical roll ofsmaller diameter on the opposite side of this thrust contact thehorizontal rolland thus absorb the side-slip of the horizontal roll,thereby completely solving the problems of conventional rolling.

The following IS a concrete explanation of the present invention usingFIG 3 and FIG. 5. In these figures are shown rolls for producing railsfrom a prefigured steel piece having a part to become the thicker flangeof the product thicker than the part to become the thinner flange of theproduct. First of all. a predetermined distance is maintained betweenthe upper horizontal roll 4 and the lower horizontal roll 4 so as tomaintain constant the thickness of web T; and the case 8 housing a pairof the vertical rolls 1 and 3 is placed within the same perpendicularsection of said horizontal rolls 4 and 4. In this case, the diameter ofthe vertical roll 3 on the side of the head 9 of the rail to besubjected to greater reduction is made smaller than that of the verticalroll 1 on the side of the base 10 of the rail to be subjected to smallerreduction. As shown in FIG. 3, the line connecting the contact points Qand 0 respectively of the vertical rolls 1 and 3 with the rolledmaterial is made parallel with the line connecting the centers 0 and Oof the vertical rolls, so as to make equal the projected lengths e,, ande, of biting contact of the rolls on the rolled material.

Inpractice the rolling schedule is predetermined with relation to thesize of the prefigured steel piece and that of the product, and to thenumber of passes and reduction by respective passes. The diameters ofthe vertical rolls are then determined on the basis of the aboveschedule and other items, so as to make equal said projected lengths ofbiting contact. Said vertical rolls 1 and 3 are housed in the verticalroll case 8. The difference in horizontal pressure between the verticalrolls 1 and 3 taking place during rolling does not produce bendingmoment, since the contact points Q and Q become parallel with eachother. Therefore, the difference, if any, of reduction rates between thetwo flanges will not cause the rolled material to bend. Horizontalpressure acting on the vertical rolls 1 and 3 is, as follows:

Where:

P',,: horizontal pressure acting on the vertical roll 3 on the side ofthe head of the rail.

P horizontal pressure acting on the vertical roll 1 on the side of thebase of the rail.

R: diameter of the vertical roll 1.

R: diameter ofthe vertical roll 3 Therefore, P,, P,. The difference inhorizontal pressure acting on the two vertical rolls due to thedifference in reduction between the two flanges is absorbed by thecontact of the part of the vertical roll to be subjected to smallerhorizontal pressure with the horizontal roll. In this case, however, atthe point of contact of the vertical roll with the horizontal roll,different peripheral speeds are produced, causing abrasion of the rolls,therefore, the following device will make the process more advantageousand is preferable. Sleeve rolls 11 are provided on the upper and lowerparts of the vertical roll 3 of smaller diameter (on the side of thehead of the rail) and held by bearings 13 and 14 set between said sleeverolls and the axis 12 of the vertical roll, so that the sleeve rolls 11contact the side of the horizontal rolls 4 and 4 and rotateindependently of the vertical roll 3.

Then, by means of the vertical roll 1 on the side of the base of therail which is subjected to greater horizontal pressure, the horizontalrolls 4 and 4 move toward the vertical roll 3 on the side of the head ofthe rail which is subjected to smaller horizontal pressure, causing thesleeve rolls ll of the vertical roll 3 to contact the side of thehorizontal rolls 4 and 4'. Therefore, the side of the vertical r0113which is subjected to smaller horizontal pressure, should be so made asto maintain the designed size at the time of contacting the horizontalrolls 4 and 4. Thus, the horizontal rolls 4 and 4' move the verticalroll which is subjected to smaller horizontal pressure, and

therefore. accuracy of the size of every part of the product ISmaintained while allowing the horizontal rolls 4 and 4' to slip asidesHowever. this method is effective only during the first pass.

For more concrete understanding, the present invention is explained, asfollows, using as an example, with mathematic formulas, the rolling of aprefigured steel piece having two flanges of the same thickness into aH-shaped steel product having flanges of a 1:3 ratio of thickness. Thefollowing is the definition of signs used in the explanation (See H0.4):

THICKNESSES OF PLAN GES Ire- After 1st After 2nd After rzth figured passpass pass Product Thicker one TAD 'I T T Thinner one... Tw Tiii TatREDUCTION RATE At 1st At 2nd At nth pass pass pass Thicker one rs: rs:ran Thinner one. rm rwz rwn PROJECTED LENGTH OF BITING CONTACT [e= ZRATR=Diameter of roll AT= Reduction] At 1st At 2nd At nth Pass pass passThicker one m m: fan Thinner one. (WI we Ewn Diameter of vertical rollThicker one: R Thinner one: R Ratio of rolls in diameter: a R /RwReduction A1 'l/ A Aly W1 N W wi Since A1= wu S0 A A1= w Twi This meansthat if the proportion of reduction is reverse to the proportion ofdiameters of vertical rolls, the projected lengths of biting contact ofthe rolls become equal.

Also,

T T AT AO Al AO (1 TAI)TAO In the same manner,

Wl wo ATW1: wo w1 wo= w1) wo At the 2nd pass, m wi ATWL': l 'wz) wiHowever. if the ratiose to.) of the diameters of the rolls are the samefor all the passes; and r +2' r For rolling a prefigured steel piecehaving flanges of the same thickness into a H-shaped steel producthaving flanges of a ratio of 1:3 of thickness, during which rolling thereduction rates at each pass are 0.1 and 0.15 respectively for thethicker flange and the thinner flange, the required number of passes r=O.l5, T =O.10 and TA0=TA0 Since That is, the desired product will beobtained at the 12th pass.

However, in actual case where the thicknesses of flanges of theprefigured steel piece, those of the desired product, the diameter ofeither roll and the reduction rate of each roll are already known, thediameter of the other roll can be easily obtained from the reverseproportion of reduction rates. As mentioned above, the, presentinvention makes it possible to greatly stabilize rolling operations forthe production of H- shaped steel products having flanges of differentthicknesses and similarly shaped steel products, by equalizing theprojected lengths of biting contact of the two rolls on the rolledmaterial, thereby eliminating bend and torsion of the rolled materialcaused by horizontal pressure.

However, in addition to the above relationship, successful rolling canbe attained also by making nearly equal the projected lengths of bitingcontact of the rolls by making the diameter of the roll which issubjected to the greater reduction rate, smaller than that of the otherroll. In other words, when producing products having flanges ofdifferent thicknesses from a material piece having flanges of the samethickness, it is natural that the difference in stretching rate shouldoccur at every pass. However, even in the ordinary type of rolling forthe production of H-shaped steel products having flanges of the samethickness, these flanges are not always the same in stretching rate.This is due mostly to play of parts of the rolling mill or difficulty inobtaining rolled materials of a desired size.

The present invention makes it possible to produce products havingflanges of different desired thicknesses by taking up the greatestdifference of allowance of stretching rate between the two flanges andby carrying out the rolling operation several times taking intoconsideration the difference of allowance of stretching rate between theflanges for each rolling operation.

Whatlclaim is n I In the rolling of steel material with the universalrolling mill, which includes a pair of vertical rolls and a pair ofhorizontal rolls. into asymmetrical H-shaped products having flanges ofdifferent thicknesses and similarly shaped products, the improvementcomprising the steps of providing one of said air of vertical rolls witha smaller diameter than the other, and causing said pair of verticalrolls to contact said steel material such that a line connecting theinitial points of contact of said vertical rolls with said material isparallel to a line connecting the centers of said vertical rolls,thereby causing the projected lengths of biting contact of said verticalrolls with said material to be equal.

2. In a universal rolling mill for making asymmetrical H- shapedproducts having flanges of different thicknesses and similarly shapedproducts, said mill comprising a pair of horizontal rolls and a pair ofvertical rolls, said vertical rolls positioned to roll said flanges, theimprovement wherein the diameter of one of said vertical rolls issmaller than that of the other, such difference in diametercorresponding to the difference in thickness of said flanges, andcomprising a pair of sleeve rolls mounted on said one of said verticalrolls having the smaller diameter, said pair of sleeve rolls contactingsaid horizontal rolls.

3. In a universal rolling mill as claimed in claim 2, wherein saidsleeve rolls are mounted around the axis at the upper and lower parts ofsaid vertical roll having the smaller diameter, said small diametervertical roll and said sleeve rolls being mounted to rotateindependently.

1. In the rolling of steel material with the universal rolling mill,which includes a pair of vertical rolls and a pair of horizontal rolls,into asymmetrical H-shaped products having flanges of differentthicknesses and similarly shaped products, the improvement comprisingthe steps of providing one of said pair of vertical rolls with a smallerdiameter than the other, and causing said pair of vertical rolls tocontact said steel material such that a line connecting the initialpoints of contact of said vertical rolls with said material is parallelto a line connecting the centers of said vertical rolls, thereby causingthe projected lengths of biting contact of said vertical rolls with saidmaterial to be equal.
 2. In a universal rolling mill for makingasymmetrical H-shaped products having flanges of different thicknessesand similarly shaped products, said mill comprising a pair of horizontalrolls and a pair of vertical rolls, said vertical rolls positioned toroll said flanges, the improvement wherein the diameter of one of saidvertical rolls is smaller than that of the other, such difference indiameter corresponding to the difference in thickness of said flanges,and comprising a pair of sleeve rolls mounted on said one of saidvertical rolls having the smaller diameter, said pair of sleeve rollscontacting said horizontal rolls.
 3. In a universal rolling mill asclaimed in claim 2, wherein said sleeve rolls are mounted around theaxis at the upper and lower parts of said vertical roll having thesmaller diameter, said small diameter vertical roll and said sleeverolls being mounted to rotate independently.